The third ESA-developed satellite carrying four Earth-observing instruments was launched today, ready to provide a 'bigger picture' for Europe's Copernicus environment programme.

The 1150 kg Sentinel-3A satellite was carried into orbit on a Rockot launcher from Plesetsk, Russia, at 17:57 GMT (18:57 CET; 20:57 local time) on 16 February.

After a first burn starting about five minutes after liftoff and a second about 70 min later, Rockot's upper stage delivered Sentinel-3A into its planned orbit, 815 km above Earth. The satellite separated 79 min into the flight.

The first signal from Sentinel-3A was received after 92 min by the Kiruna station in Sweden. Telemetry links and attitude control were then established by controllers at ESA's ESOC operations centre in Darmstadt, Germany, allowing them to monitor the health of the satellite.

After the launch and the early orbit phase of three days, controllers will begin checking that all the satellite elements are working and subsequently calibrate the instruments to commission the satellite. The mission is expected to begin operations in five months.

"With the successful launch of Sentinel-3 we are now looking forward to how our teams of experts will steer this mission into its operational life - like they have done the first two satellites of the series," said ESA Director General Jan Woerner.

"This is another demonstration of the broad range of competence we have at ESA from the early design phase until the operational mission in orbit."

The mission is the third of six families of dedicated missions that make up the core of Europe's Copernicus environmental monitoring network. Copernicus relies on the Sentinels and contributing missions to provide data for monitoring the environment and supporting civil security activities. Sentinel-3 carries a series of cutting-edge sensors to do just that.

Over oceans, it measures the temperature, colour and height of the sea surface as well as the thickness of sea ice. These measurements will be used, for example, to monitor changes in Earth's climate and for more hands-on applications such as marine pollution and biological productivity.

Over land, this innovative mission will monitor wildfires, map the way land is used, check vegetation health and measure the height of rivers and lakes.

"This is the third of the Sentinel satellites launched in the less than two years - and it is certainly a special moment. It also marks a new era for the Copernicus Services, with Sentinel-3 providing a whole range of new data with unprecedented coverage of the oceans," said the Director of ESA's Earth Observation Programmes, Volker Liebig.

Sentinel-3B, its twin satellite, is scheduled for launch next year.

Data from all the Sentinels are used worldwide and are free of charge for all users.

Why was this payload launched on a Rokot, as it's not like ESA is short of launchers of various different classes?

They have often launched LEO satellites on small russian launchers in the past. Before Vega it made more sense I guess.Even now, I don't think there is any requirement for ESA projets to launch on European launchers, so they might go for the cheaper option to meet budget constraints (so not Vega...). There might also be launcher manifest availability issues.

This year, both Sentinel 5p and Sentinel 2B are planned to be launched on Rokot.

Why was this payload launched on a Rokot, as it's not like ESA is short of launchers of various different classes?

They have often launched LEO satellites on small russian launchers in the past. Before Vega it made more sense I guess.Even now, I don't think there is any requirement for ESA projets to launch on European launchers, so they might go for the cheaper option to meet budget constraints (so not Vega...). There might also be launcher manifest availability issues.

This year, both Sentinel 5p and Sentinel 2B are planned to be launched on Rokot.

Thank you. I just kind of assumed these would be the kind of payloads that Vega was designed and built for.

With the change to Ariane 6 and vega C the European member states and institutions commit themselfs to use at least 5 launches from arianespace per year (possibly more if it only counts for Ariane6's). For the first fleet of sentinels (2a/b, 3a/b) it was decided to launch one of both on (then unproven) vega and on Rockot. So 2A and 3b are launched by vega and 2B and 3A are launched by Rockot.Sentinel 5p will also be launched on Rockot (cheaper an was proven). the Sentinel 1s are to heavy for vega. So they launch (with secondaries) on Soyuz. Most likely all C and D sentinels will be launched by Vega (C), if so many launches are available.

The planning for rokot launches used to be spread out over two years. Sentinel 5p in 2015 and Sentinel 3A and 2B this year 2016. But the sensor Tropomy from 5p was delayed, and thus the launch.Also Sentinel 1B will launch in march if I'm not mistaken. Next year Sentinel 3B on vega and than it will be quiet for a couple of years.Until sentinel 5 on MetOp-SG A, sentinel 4 on MTG-S1 and Jason-CS/sentinel 6and than soon the second batch of sentinel 1, 2 & 3.Also the EDRS communicationat satellites (two of them, one already launched on proton) are planned for this year. That's why ESA's earth observation and launchers budget are large this year.

Out of planning curiosity are 5p and 2b planned to have similar launch profiles to 3A? I ask because assuming they happen while I am still up here I would love to capture better video of a reentry the next time around.